Checking Current Draw

[Little Bill]

Will an amp clamp measure DC current? I think I have a drain on my van battery and want to check if there is a drain with nothing running.

 

[rambojoe]

If you have a dc amp on the selector, then yes.
They make very simple non contact dc meters, sold on amazon...

 

[jim dungar]

Will an amp clamp measure DC current? I think I have a drain on my van battery and want to check if there is a drain with nothing running.

Usually not. DC clamps usually use some type of Hall effect sensing which is not always added to the low and moderate cost meters.

 

[Little Bill]

I don't have my meter handy and don't remember if it has a DC setting for amps.

 

[ptonsparky]

.my brother was looking for a current draw draining his. The suggestion was to measure the VD across each fuse.

I had a DC amp clamp so used it instead.

 

[ptonsparky]

IDR, but I think it was 4 millivolt DC limit.

 

[hillbilly1]

My Fluke clamp meter has a DC setting, but most cheaper meters will do DC up to 10 amps when the leads are put in series with the load. If your looking for a parasite draw, that should be sufficient.

 

[Seven-Delta-FortyOne]

Mine does. I have the Fluke 289 with the i410 clamp meter. It does dc current. I used it to check the exact same thing. Pretty accurate.

 

[rambojoe]

I don't have my meter handy and don't remember if it has a DC setting for amps.

Order a cheapie auto inductive meter.. itll be there tmrw..

 

[Dsg319]

Got a south wire cheap amp clamp that has both ac and dc.

But even near no wires the dc always reads around 0.40amps

 

[hillbilly1]

Modern vehicles are a pain to trace out current draws, because some loads stay on for quite a while after exiting. My dashcam kills my battery over a weekend if I don’t unplug it.

 

[ActionDave]

I've traced a draining battery hooking my multi meter up in series with the battery, but like hillbilly says it's an involved process because you have to wait thirty minutes, check the meter, pull a fuse, wait another thirty minutes, pull a fuse......lather, rinse, repeat.

 

[fastline]

I use a DC clamp meter for this all the time. Rez down to 1mA.

 

[Little Bill]

I had the battery tested and it showed good. I went ahead and had them install a new battery because mine is 4 years old. I want to start testing with a good battery.
I don't think my van has much drawing current at rest. I think the clock and probably the computer. It's a 2007 F100 with nothing extra like power windows.
I plan to put my meter in series with the battery via the negative post to the negative cable to test.

 

[fastline]

I had the battery tested and it showed good. I went ahead and had them install a new battery because mine is 4 years old. I want to start testing with a good battery.
I don't think my van has much drawing current at rest. I think the clock and probably the computer. It's a 2007 F100 with nothing extra like power windows.
I plan to put my meter in series with the battery via the negative post to the negative cable to test.

Good chance that won't end well. Big inrush on many vehicles. Need current protection in series. ECMs go through several stages of power down. If you get down to about 20mA or less, that's usually as good as you can do.

 

[ptonsparky]

4-5 years is about all you get from a battery

 

[Little Bill]

Good chance that won't end well. Big inrush on many vehicles. Need current protection in series. ECMs go through several stages of power down. If you get down to about 20mA or less, that's usually as good as you can do.

I'm not talking about starting, or running, while the meter is in series. I'm talking about with nothing on, doors closed, key out of the ignition. Then if it shows a draw, I will pull fuses until I find the circuit that is drawing current.

 

[jim dungar]

Some cars have more losses than others and there is little you can do about it.
A poorly designed computer might waste a lot of power as it sits there waiting to hear the signal from the key fob or trying to maintain the GPS signal whether you use them or not.

Accoding online forums, my Honda CR-V is evidently one of these bad designs. During the a winter it needs to be run for 20 minutes once every ten days, during the summer it can go 3 weeks. When the weather gets below zero I put on a trickle charger.

 

[kwired]

My Fluke clamp meter has a DC setting, but most cheaper meters will do DC up to 10 amps when the leads are put in series with the load. If your looking for a parasite draw, that should be sufficient.

And with vehicles with electronically controlled items, if you are connecting the leads between battery post and battery lead, you likely need to wait up to a few minutes as some loads will draw current as soon as energized but will drop off after a little time has passed. I have done this then once a few minutes had passed current draw was reduced, but you could then pull fuses one at a time and get an idea where any remaining current may be going to.

 

[fastline]

I'm not talking about starting, or running, while the meter is in series. I'm talking about with nothing on, doors closed, key out of the ignition. Then if it shows a draw, I will pull fuses until I find the circuit that is drawing current.

Again, good luck. There are a lot of capacitors that load up with key on. Consider this an inrush hit of a motor. It's not trivial.